upload tizen1.0 sourceHEADmaster2.0alpha

1 files changed, 507 insertions, 0 deletions

diff --git a/fs/file_table.c b/fs/file_table.c
new file mode 100644
index 00000000..a04bdd81
--- /dev/null
+++ b/fs/file_table.c
@@ -0,0 +1,507 @@
+/*
+ *  linux/fs/file_table.c
+ *
+ *  Copyright (C) 1991, 1992  Linus Torvalds
+ *  Copyright (C) 1997 David S. Miller (davem@caip.rutgers.edu)
+ */
+
+#include <linux/string.h>
+#include <linux/slab.h>
+#include <linux/file.h>
+#include <linux/fdtable.h>
+#include <linux/init.h>
+#include <linux/module.h>
+#include <linux/fs.h>
+#include <linux/security.h>
+#include <linux/eventpoll.h>
+#include <linux/rcupdate.h>
+#include <linux/mount.h>
+#include <linux/capability.h>
+#include <linux/cdev.h>
+#include <linux/fsnotify.h>
+#include <linux/sysctl.h>
+#include <linux/lglock.h>
+#include <linux/percpu_counter.h>
+#include <linux/percpu.h>
+#include <linux/ima.h>
+
+#include <asm/atomic.h>
+
+#include "internal.h"
+
+/* sysctl tunables... */
+struct files_stat_struct files_stat = {
+	.max_files = NR_FILE
+};
+
+DECLARE_LGLOCK(files_lglock);
+DEFINE_LGLOCK(files_lglock);
+
+/* SLAB cache for file structures */
+static struct kmem_cache *filp_cachep __read_mostly;
+
+static struct percpu_counter nr_files __cacheline_aligned_in_smp;
+
+static inline void file_free_rcu(struct rcu_head *head)
+{
+	struct file *f = container_of(head, struct file, f_u.fu_rcuhead);
+
+	put_cred(f->f_cred);
+	kmem_cache_free(filp_cachep, f);
+}
+
+static inline void file_free(struct file *f)
+{
+	percpu_counter_dec(&nr_files);
+	file_check_state(f);
+	call_rcu(&f->f_u.fu_rcuhead, file_free_rcu);
+}
+
+/*
+ * Return the total number of open files in the system
+ */
+static int get_nr_files(void)
+{
+	return percpu_counter_read_positive(&nr_files);
+}
+
+/*
+ * Return the maximum number of open files in the system
+ */
+int get_max_files(void)
+{
+	return files_stat.max_files;
+}
+EXPORT_SYMBOL_GPL(get_max_files);
+
+/*
+ * Handle nr_files sysctl
+ */
+#if defined(CONFIG_SYSCTL) && defined(CONFIG_PROC_FS)
+int proc_nr_files(ctl_table *table, int write,
+                     void __user *buffer, size_t *lenp, loff_t *ppos)
+{
+	files_stat.nr_files = get_nr_files();
+	return proc_dointvec(table, write, buffer, lenp, ppos);
+}
+#else
+int proc_nr_files(ctl_table *table, int write,
+                     void __user *buffer, size_t *lenp, loff_t *ppos)
+{
+	return -ENOSYS;
+}
+#endif
+
+/* Find an unused file structure and return a pointer to it.
+ * Returns NULL, if there are no more free file structures or
+ * we run out of memory.
+ *
+ * Be very careful using this.  You are responsible for
+ * getting write access to any mount that you might assign
+ * to this filp, if it is opened for write.  If this is not
+ * done, you will imbalance int the mount's writer count
+ * and a warning at __fput() time.
+ */
+struct file *get_empty_filp(void)
+{
+	const struct cred *cred = current_cred();
+	static int old_max;
+	struct file * f;
+
+	/*
+	 * Privileged users can go above max_files
+	 */
+	if (get_nr_files() >= files_stat.max_files && !capable(CAP_SYS_ADMIN)) {
+		/*
+		 * percpu_counters are inaccurate.  Do an expensive check before
+		 * we go and fail.
+		 */
+		if (percpu_counter_sum_positive(&nr_files) >= files_stat.max_files)
+			goto over;
+	}
+
+	f = kmem_cache_zalloc(filp_cachep, GFP_KERNEL);
+	if (f == NULL)
+		goto fail;
+
+	percpu_counter_inc(&nr_files);
+	if (security_file_alloc(f))
+		goto fail_sec;
+
+	INIT_LIST_HEAD(&f->f_u.fu_list);
+	atomic_long_set(&f->f_count, 1);
+	rwlock_init(&f->f_owner.lock);
+	f->f_cred = get_cred(cred);
+	spin_lock_init(&f->f_lock);
+	eventpoll_init_file(f);
+	/* f->f_version: 0 */
+	return f;
+
+over:
+	/* Ran out of filps - report that */
+	if (get_nr_files() > old_max) {
+		printk(KERN_INFO "VFS: file-max limit %d reached\n",
+					get_max_files());
+		old_max = get_nr_files();
+	}
+	goto fail;
+
+fail_sec:
+	file_free(f);
+fail:
+	return NULL;
+}
+
+/**
+ * alloc_file - allocate and initialize a 'struct file'
+ * @mnt: the vfsmount on which the file will reside
+ * @dentry: the dentry representing the new file
+ * @mode: the mode with which the new file will be opened
+ * @fop: the 'struct file_operations' for the new file
+ *
+ * Use this instead of get_empty_filp() to get a new
+ * 'struct file'.  Do so because of the same initialization
+ * pitfalls reasons listed for init_file().  This is a
+ * preferred interface to using init_file().
+ *
+ * If all the callers of init_file() are eliminated, its
+ * code should be moved into this function.
+ */
+struct file *alloc_file(struct path *path, fmode_t mode,
+		const struct file_operations *fop)
+{
+	struct file *file;
+
+	file = get_empty_filp();
+	if (!file)
+		return NULL;
+
+	file->f_path = *path;
+	file->f_mapping = path->dentry->d_inode->i_mapping;
+	file->f_mode = mode;
+	file->f_op = fop;
+
+	/*
+	 * These mounts don't really matter in practice
+	 * for r/o bind mounts.  They aren't userspace-
+	 * visible.  We do this for consistency, and so
+	 * that we can do debugging checks at __fput()
+	 */
+	if ((mode & FMODE_WRITE) && !special_file(path->dentry->d_inode->i_mode)) {
+		file_take_write(file);
+		WARN_ON(mnt_clone_write(path->mnt));
+	}
+	ima_counts_get(file);
+	return file;
+}
+EXPORT_SYMBOL(alloc_file);
+
+/**
+ * drop_file_write_access - give up ability to write to a file
+ * @file: the file to which we will stop writing
+ *
+ * This is a central place which will give up the ability
+ * to write to @file, along with access to write through
+ * its vfsmount.
+ */
+void drop_file_write_access(struct file *file)
+{
+	struct vfsmount *mnt = file->f_path.mnt;
+	struct dentry *dentry = file->f_path.dentry;
+	struct inode *inode = dentry->d_inode;
+
+	put_write_access(inode);
+
+	if (special_file(inode->i_mode))
+		return;
+	if (file_check_writeable(file) != 0)
+		return;
+	mnt_drop_write(mnt);
+	file_release_write(file);
+}
+EXPORT_SYMBOL_GPL(drop_file_write_access);
+
+/* the real guts of fput() - releasing the last reference to file
+ */
+static void __fput(struct file *file)
+{
+	struct dentry *dentry = file->f_path.dentry;
+	struct vfsmount *mnt = file->f_path.mnt;
+	struct inode *inode = dentry->d_inode;
+
+	might_sleep();
+
+	fsnotify_close(file);
+	/*
+	 * The function eventpoll_release() should be the first called
+	 * in the file cleanup chain.
+	 */
+	eventpoll_release(file);
+	locks_remove_flock(file);
+
+	if (unlikely(file->f_flags & FASYNC)) {
+		if (file->f_op && file->f_op->fasync)
+			file->f_op->fasync(-1, file, 0);
+	}
+	if (file->f_op && file->f_op->release)
+		file->f_op->release(inode, file);
+	security_file_free(file);
+	ima_file_free(file);
+	if (unlikely(S_ISCHR(inode->i_mode) && inode->i_cdev != NULL))
+		cdev_put(inode->i_cdev);
+	fops_put(file->f_op);
+	put_pid(file->f_owner.pid);
+	file_sb_list_del(file);
+	if (file->f_mode & FMODE_WRITE)
+		drop_file_write_access(file);
+	file->f_path.dentry = NULL;
+	file->f_path.mnt = NULL;
+	file_free(file);
+	dput(dentry);
+	mntput(mnt);
+}
+
+void fput(struct file *file)
+{
+	if (atomic_long_dec_and_test(&file->f_count))
+		__fput(file);
+}
+
+EXPORT_SYMBOL(fput);
+
+struct file *fget(unsigned int fd)
+{
+	struct file *file;
+	struct files_struct *files = current->files;
+
+	rcu_read_lock();
+	file = fcheck_files(files, fd);
+	if (file) {
+		if (!atomic_long_inc_not_zero(&file->f_count)) {
+			/* File object ref couldn't be taken */
+			rcu_read_unlock();
+			return NULL;
+		}
+	}
+	rcu_read_unlock();
+
+	return file;
+}
+
+EXPORT_SYMBOL(fget);
+
+/*
+ * Lightweight file lookup - no refcnt increment if fd table isn't shared.
+ *
+ * You can use this instead of fget if you satisfy all of the following
+ * conditions:
+ * 1) You must call fput_light before exiting the syscall and returning control
+ *    to userspace (i.e. you cannot remember the returned struct file * after
+ *    returning to userspace).
+ * 2) You must not call filp_close on the returned struct file * in between
+ *    calls to fget_light and fput_light.
+ * 3) You must not clone the current task in between the calls to fget_light
+ *    and fput_light.
+ *
+ * The fput_needed flag returned by fget_light should be passed to the
+ * corresponding fput_light.
+ */
+struct file *fget_light(unsigned int fd, int *fput_needed)
+{
+	struct file *file;
+	struct files_struct *files = current->files;
+
+	*fput_needed = 0;
+	if (likely((atomic_read(&files->count) == 1))) {
+		file = fcheck_files(files, fd);
+	} else {
+		rcu_read_lock();
+		file = fcheck_files(files, fd);
+		if (file) {
+			if (atomic_long_inc_not_zero(&file->f_count))
+				*fput_needed = 1;
+			else
+				/* Didn't get the reference, someone's freed */
+				file = NULL;
+		}
+		rcu_read_unlock();
+	}
+
+	return file;
+}
+
+void put_filp(struct file *file)
+{
+	if (atomic_long_dec_and_test(&file->f_count)) {
+		security_file_free(file);
+		file_sb_list_del(file);
+		file_free(file);
+	}
+}
+
+static inline int file_list_cpu(struct file *file)
+{
+#ifdef CONFIG_SMP
+	return file->f_sb_list_cpu;
+#else
+	return smp_processor_id();
+#endif
+}
+
+/* helper for file_sb_list_add to reduce ifdefs */
+static inline void __file_sb_list_add(struct file *file, struct super_block *sb)
+{
+	struct list_head *list;
+#ifdef CONFIG_SMP
+	int cpu;
+	cpu = smp_processor_id();
+	file->f_sb_list_cpu = cpu;
+	list = per_cpu_ptr(sb->s_files, cpu);
+#else
+	list = &sb->s_files;
+#endif
+	list_add(&file->f_u.fu_list, list);
+}
+
+/**
+ * file_sb_list_add - add a file to the sb's file list
+ * @file: file to add
+ * @sb: sb to add it to
+ *
+ * Use this function to associate a file with the superblock of the inode it
+ * refers to.
+ */
+void file_sb_list_add(struct file *file, struct super_block *sb)
+{
+	lg_local_lock(files_lglock);
+	__file_sb_list_add(file, sb);
+	lg_local_unlock(files_lglock);
+}
+
+/**
+ * file_sb_list_del - remove a file from the sb's file list
+ * @file: file to remove
+ * @sb: sb to remove it from
+ *
+ * Use this function to remove a file from its superblock.
+ */
+void file_sb_list_del(struct file *file)
+{
+	if (!list_empty(&file->f_u.fu_list)) {
+		lg_local_lock_cpu(files_lglock, file_list_cpu(file));
+		list_del_init(&file->f_u.fu_list);
+		lg_local_unlock_cpu(files_lglock, file_list_cpu(file));
+	}
+}
+
+#ifdef CONFIG_SMP
+
+/*
+ * These macros iterate all files on all CPUs for a given superblock.
+ * files_lglock must be held globally.
+ */
+#define do_file_list_for_each_entry(__sb, __file)		\
+{								\
+	int i;							\
+	for_each_possible_cpu(i) {				\
+		struct list_head *list;				\
+		list = per_cpu_ptr((__sb)->s_files, i);		\
+		list_for_each_entry((__file), list, f_u.fu_list)
+
+#define while_file_list_for_each_entry				\
+	}							\
+}
+
+#else
+
+#define do_file_list_for_each_entry(__sb, __file)		\
+{								\
+	struct list_head *list;					\
+	list = &(sb)->s_files;					\
+	list_for_each_entry((__file), list, f_u.fu_list)
+
+#define while_file_list_for_each_entry				\
+}
+
+#endif
+
+int fs_may_remount_ro(struct super_block *sb)
+{
+	struct file *file;
+	/* Check that no files are currently opened for writing. */
+	lg_global_lock(files_lglock);
+	do_file_list_for_each_entry(sb, file) {
+		struct inode *inode = file->f_path.dentry->d_inode;
+
+		/* File with pending delete? */
+		if (inode->i_nlink == 0)
+			goto too_bad;
+
+		/* Writeable file? */
+		if (S_ISREG(inode->i_mode) && (file->f_mode & FMODE_WRITE))
+			goto too_bad;
+	} while_file_list_for_each_entry;
+	lg_global_unlock(files_lglock);
+	return 1; /* Tis' cool bro. */
+too_bad:
+	lg_global_unlock(files_lglock);
+	return 0;
+}
+
+/**
+ *	mark_files_ro - mark all files read-only
+ *	@sb: superblock in question
+ *
+ *	All files are marked read-only.  We don't care about pending
+ *	delete files so this should be used in 'force' mode only.
+ */
+void mark_files_ro(struct super_block *sb)
+{
+	struct file *f;
+
+retry:
+	lg_global_lock(files_lglock);
+	do_file_list_for_each_entry(sb, f) {
+		struct vfsmount *mnt;
+		if (!S_ISREG(f->f_path.dentry->d_inode->i_mode))
+		       continue;
+		if (!file_count(f))
+			continue;
+		if (!(f->f_mode & FMODE_WRITE))
+			continue;
+		spin_lock(&f->f_lock);
+		f->f_mode &= ~FMODE_WRITE;
+		spin_unlock(&f->f_lock);
+		if (file_check_writeable(f) != 0)
+			continue;
+		file_release_write(f);
+		mnt = mntget(f->f_path.mnt);
+		/* This can sleep, so we can't hold the spinlock. */
+		lg_global_unlock(files_lglock);
+		mnt_drop_write(mnt);
+		mntput(mnt);
+		goto retry;
+	} while_file_list_for_each_entry;
+	lg_global_unlock(files_lglock);
+}
+
+void __init files_init(unsigned long mempages)
+{ 
+	int n; 
+
+	filp_cachep = kmem_cache_create("filp", sizeof(struct file), 0,
+			SLAB_HWCACHE_ALIGN | SLAB_PANIC, NULL);
+
+	/*
+	 * One file with associated inode and dcache is very roughly 1K.
+	 * Per default don't use more than 10% of our memory for files. 
+	 */ 
+
+	n = (mempages * (PAGE_SIZE / 1024)) / 10;
+	files_stat.max_files = n; 
+	if (files_stat.max_files < NR_FILE)
+		files_stat.max_files = NR_FILE;
+	files_defer_init();
+	lg_lock_init(files_lglock);
+	percpu_counter_init(&nr_files, 0);
+}